Start with the SG-1 Season 8 premiere, "New Order: Part 1 & 2".
This season features a major escalation and ultimate resolution of the Replicator threat. Stargate SG1 - Season 8
If you are watching for the first time, it is highly recommended to follow the to keep track of major crossovers and plot developments between SG-1 and Atlantis . Start with the SG-1 Season 8 premiere, "New
Jack O'Neill is promoted to Brigadier General and takes command of the SGC, succeeding General Hammond. particularly involving Ba'al and the Replicators.
The power vacuum left by Anubis leads to significant shifts in the Goa'uld hierarchy, particularly involving Ba'al and the Replicators.